The research will evaluate reciprocal influences between mentally retarded children and their families. It will include a 5-year follow-up (Wave 3) of a sample of 150 families of school-age children (6-18 years old) with mild and moderate mental retardation, and a matched sample of 50 comparison families with typically developing children of the same age. The study will focus on family interactions as proximal and potentially modifiable predictors of adjustment for all family members, and thus will suggest avenues for interventions to prevent deterioration in social and cognitive adjustment for mentally retarded children, and to avoid distress and disruption for the other family members. All family members are included in the research. It will test the hypothesis that characteristics of the child, marital quality, family stress and coping resources each influence the quality of supportive, aversive, and behavior-management interactions between the mentally retarded child and other family members. In turn, interactions should affect the child's future psychosocial adjustment and cognitive and social development, and the future well-being of the family members. This third assessment also will explicate cognitive factors for the parents which can either foster positive adaptation or lead to conflict, hostility, and aversive interactions with the child. Additionally, at Time 3 the families of mentally retarded children will be contrasted with two new comparison groups, families with children with a chronic illness or physical handicap (n=60), and families of behavior disordered children (n=60). These additional comparisons will control for the effects of stress associated with coping with a chronic handicap, physical disabilities, and child behavior problems on family adaptation and subsequent child functioning, and thus will identify unique processes by which mentally retarded children and their families influence each other.